Sodium hydride → tert-butyl 4-{2-[2-(1H-imidazo[4,5-c]quinolin-1-yl)butoxy]ethyl}piperidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Under a nitrogen atmosphere, 2-(1H-imidazo[4,5-c]quinolin-1-yl)butan-1-ol (6.5 g, 26.9 mmol) was added in three portions to a suspension of sodium hydride (1.4 g of 60%, 35.0 mmol) in anhydrous N,N-dimethylformamide. The reaction mixture was allowed to stir for 45 minutes by which time gas evolution had ceased. Tert-butyl 4-(2-iodoethyl)piperidine-1-carboxylate (10.05 g, 29.6 mmol) was added dropwise over a period of 15 minutes. The reaction mixture was allowed to stir at ambient temperature for 2.5 hrs; then it was heated to 100° C. and stirred overnight. Analysis by HPLC showed that the reaction was about 35% complete. Saturated ammonium chloride solution was added, the resulting mixture was allowed to stir for 20 minutes and then it was extracted with ethyl acetate (2×). The ethyl acetate extracts were washed with water (2×) and then with brine, combined, dried over sodium sulfate, filtered and then concentrated under reduced pressure to provide a brown oil. The oil was purified by column chromatography (silica gel eluting sequentially with 30% ethyl acetate in hexanes, 50% ethyl acetate in hexanes, and ethyl acetate) to provide 2.2 g of tert-butyl 4-{2-[2-(1H-imidazo[4,5-c]quinolin-1-yl)butoxy]ethyl}piperidine-1-carboxylate.

Provenance & Evidence